The invention relates to a method for the separation of polymer mixtures and a device for carrying out said method, of application to the separation of polymer mixtures on processing thermoplastic plastics. According to the invention, a polymer mixture for separation is fused or plastified in a shear gap of a shear element with annular flow channels of varying diameter, whereby fractions of the polymer mixture are led off from the screw gap in at least two locations, which have annular flow paths of varying diameter. The device comprises a separating chamber (1) with conical inner walls, in the middle of which a rotating mixing rotor (2) with an outer conical form is mounted to form a shear gap (3), whereby the device is provided with one introduction channel (4) and at least two outlet channels (5).